Connection method of thermoplastic resin long body

ABSTRACT

A connection method for interconnecting end portions of a thermoplastic resin long body in which conductive unstretchable members are embedded within the thermoplastic resin along a longitudinal direction, wherein the unstretchable members in each of specific sections in the both end portions of the thermoplastic resin long body are heated using an induction heating portion so that the thermoplastic resin coating the unstretchable members is removed by melting for the unstretchable members to be exposed, after which the both end portions are interconnected while they are held in a state where the unstretchable members being exposed in the respective end portions are butt-connected to each other.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a connection method of a thermoplasticresin long body for interconnecting the end portions of a long body madeof thermoplastic resin in which conductive unstretchable members areembedded within the thermoplastic resin, such as a moving handrail of apassenger conveyer or an escalator.

2. Background Art

A moving handrail of a passenger conveyer, an escalator, or the likeincludes, as chief members, a handrail main body normally made of rubberor a thermoplastic resin material, a large number of long slender coppercables (tensile bodies) embedded within the handrail main body along thelongitudinal direction, and a canvas laminated to the under side of thehandrail main body.

The copper cables function as a stretch preventing member that providesthe handrail with a desired strength in the longitudinal direction whileat the same time they are allowed to bend in the vertical direction tomake the handrail movable about rollers and a drive mechanism. Thecanvas is bonded to the handrail in a T-shaped channel at the bottom ofthe handrail and is furnished with a function to reduce a frictionalcoefficient between the main body guide and the moving handrail.

The moving handrail is first formed as a thermoplastic resin long bodyand completed as a final product when it is processed in the form of aloop having a desired length by interconnecting the end portions of thelong body. For example, JP-T-2000-507893 proposes to cut the endportions in alternating complex patterns with a cutting tool in order toobtain a sufficient bonding strength when the end portions of the longbody are interconnected. The process to form the alternating patterns inthe end portions, however, requires a cutting process to separate thehandrail main body, a large number of copper cables, and the canvas aswell as a cutting process to form the patterns.

The cutting processes using a cutting tool as above have a problem thatit takes a long processing time to process thermoplastic resin widelyand long (or deeply and long). In particular, the process to separatethe handrail main body and a large number of copper cables requires acertain degree of processing accuracy. This raises a problem that theprocessing speed cannot be increased.

In addition, by merely butt-connecting the tips of the copper cableswhen interconnecting the end portions of the thermoplastic resin longbody, in a case where the long body is used as a moving handrail, therearises a problem resulting from aging that the copper cables breakthrough the thermoplastic resin and come out to the surface of themoving handrail.

SUMMARY OF THE INVENTION

The invention was devised to solve the problems discussed above and hasan object to provide a connection method for connecting, in a short timeand in a reliable manner, the end portions of a long body made ofthermoplastic resin in which conductive unstretchable members areembedded within the thermoplastic resin along the longitudinaldirection, such as a moving handrail of a passenger conveyer or anescalator.

A connection method of a thermoplastic resin long body according to oneaspect of the invention for interconnecting end portions of a long bodymade of thermoplastic resin in which conductive unstretchable membersare embedded within the thermoplastic resin along a longitudinaldirection is configured in such a manner that the unstretchable membersin each of specific sections in the both end portions of thethermoplastic resin long body are heated using an induction heatingportion so that the thermoplastic resin coating the unstretchablemembers in the specific sections is removed by melting for theunstretchable members to be exposed, after which the both end portionsare interconnected while the both ends are held in a state where theunstretchable members being exposed in one end portion and in the otherend portion are butt-connected to each other.

According to the invention, by heating the unstretchable members per seto a desired temperature (basically, a temperature at which thethermoplastic resin melts) by the induction heating portion, it becomespossible to separate the thermoplastic resin and the unstretchablemembers by melting the thermoplastic resin coating the periphery of theunstretchable members. The thermoplastic resin and the unstretchablemembers can be therefore separated in a short time and in a reliablemanner.

Also, in a case where the thermoplastic resin and the unstretchablemembers are separated, the thermoplastic resin and the unstretchablemembers can be processed separately as individual members when formingthe end portion shapes necessary to interconnect the end portions of thethermoplastic resin long body. This facilitates the cutting process andthe like.

In addition, because the thermoplastic resin is melted only on theperiphery of the unstretchable members, not only can the separationprocess be performed without deteriorating the quality and the functionas a moving handrail of a passenger conveyer or an escalator, but alsothe separation process can be performed at satisfactory workabilitybecause the shape as the thermoplastic resin long body remains stable.

Further, in a case where the unstretchable members are physicallyconnected to each other, not only is it possible to ensure the strengthas the moving handrail, but it is also possible to prevent deteriorationof the quality, such as an event resulting from aging that theunstretchable members protrude to the surface of the moving handrail.

The foregoing and other object, features, aspects, and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective end view of a moving handrail of a passengerconveyer;

FIG. 2A is a plan view, FIG. 2B is a side view, and FIG. 2C is an endview used to describe one step in a connection method of a resin longbody according to a first embodiment of the invention;

FIG. 3 is a plan view used to describe another step in the firstembodiment of the invention;

FIG. 4A is a plan view and FIG. 4B is a side view used to describe stillanother step in the first embodiment of the invention;

FIG. 5 is a plan view used to describe still another step in the firstembodiment of the invention;

FIG. 6A is a plan view and FIG. 6B is a side view used to describe stillanother step in the first embodiment of the invention;

FIG. 7A is a plan view and FIG. 7B is a side view used to describe stillanother step in the first embodiment of the invention;

FIG. 8A is a plane view and FIG. 8B is a side view used to describestill another step in the first embodiment of the invention;

FIG. 9A is a plan view and FIG. 9B is a side view used to describe stillanother step in the first embodiment of the invention;

FIG. 10A is an end view and FIG. 10B is a side view showing a die usedwhen interconnecting end portions of the resin long body in the firstembodiment of the invention;

FIG. 11A is a plan view and FIG. 11B is a side view used to describe onestep in a connection method of a resin long body according to a secondembodiment of the invention;

FIG. 12A is a plan view and FIG. 12B is a side view used to describeanother step in the second embodiment of the invention;

FIG. 13A and FIG. 13B are plane views used to describe another exampleof the second embodiment of the invention, FIG. 13A showing a statebefore a process is applied and FIG. 13B showing a state after theprocess is applied; and

FIG. 14 is a plan view used to describe still another example of thesecond embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 1 is perspective end view of a long body made of thermoplasticresin (hereinafter, referred to as the resin long body) 1 used forhandrails of a passenger conveyor or the like. Referring to FIG. 1, theresin long body 1 is formed of a thermoplastic resin 2, for example,urethane, conductive, long slender unstretchable members 3, for example,copper cables, embedded within the thermoplastic resin 2 and playing arole of a stretch preventing member that provides the resin long body 1with a desired strength in the longitudinal direction, and a supportingfabric 4, such as a canvas, laminated to the under side in order toreduce a frictional coefficient between the resin long body 1 and atraveling guide (not shown).

The resin long body 1 configured as above is finished as a finalproduct, such as a moving handrail of a passenger conveyer, as it isprocessed in the form of a loop having a desired length byinterconnecting the end portions.

Hereinafter, a method for interconnecting the end portions of the resinlong body 1 will be described.

Firstly, a processing method at one end of the resin long body 1 will bedescribed. As are shown in FIGS. 2A through 2C, the upper portion of thethermoplastic resin 2 is sliced as is indicated by a sliced piece 5 upto a portion C spaced apart by a predetermined distance in thelongitudinal direction from an end face A at one end of the resin longbody 1. Subsequently, cuts are made in curved thermoplastic resinportions on the right and left in an intermediate portion B between theend face A and the portion C. Finally, cuts are made from the supportingfabric 4 side while leaving the unstretchable members 3 flawless. Inthis instance, cuts are made so that the thermoplastic resin 2 of aboutseveral millimeters (for example, 1 to 2 mm) is left on the periphery ofthe unstretchable members 3.

Then, as is shown in FIG. 3, a section 1A between the end face A and theintermediate portion B of the resin long body 1, in which it is cut sothat the thermoplastic resin 2 is left only on the periphery of theunstretchable members 3, is placed in an induction heating coil servingas an induction heating portion 6. The unstretchable members 3 in thesection 1A are thus inductively heated.

The temperature of the unstretchable members 3 in the section 1A risesowing to this induction heating and so does the temperature of thethermoplastic resin 2 coating the periphery of the unstretchable member3.

When the temperature exceeds the melting temperature of thethermoplastic resin 2 (about 160° C. in the case of urethane), thestrength on the periphery of the unstretchable members 3 is lowered. Inthis instance, by pulling the thermoplastic resin 2 in the section 1A inthe longitudinal direction from the end face of the resin long body 1,as are shown in FIGS. 4A and 4B, it becomes possible to remove thethermoplastic resin 2 in the section 1A alone, thereby causing theunstretchable members 3 in the section 1A to be exposed.

In this case, in order to maintain the temperature of the unstretchablemembers 3, which are the subjects to be heated, at a constanttemperature (for example, 200° C. to 250° C. in the case of urethane) orin a predetermined pattern during the induction heating, a temperaturerise of the unstretchable members 3 is monitored by a thermo couple 7and fed back to a control system of the induction heating portion 6.

In addition, the induction heating portion 6 may be controlled not onlyto maintain the temperature of the unstretchable members 3 but also tomaintain the hardness of the thermoplastic resin 2 that is softened dueto influences of the unstretchable members 3 heated by the inductionheating portion 6 at a predetermined value.

As an example of a method for controlling the temperature of theunstretchable member 3 or the hardness of the thermoplastic resin 2 at apredetermined value, the temperature being monitored by the thermocouple 7 is fed back to the control system of an induction heatingdevice (not shown) to compare the fed back value with the predeterminedset value, so that turning ON and OFF of an output of the inductionheating device is controlled on the basis of the comparison result (theinduction heating is turned OFF when the monitored value exceeds thepredetermined value and the induction heating is turned ON when theformer is smaller than the latter).

A processing method for the other end of the resin long body 1 will nowbe described.

As is shown in FIG. 5, a portion E spaced apart by a predetermineddistance in the longitudinal direction from the end face D at the otherend of the resin long body 1 and a portion F spaced apart by apredetermined distance from the portion E in the direction opposite tothe end face D are set. The upper portion of the thermoplastic resin 2present between the end face D and the portion F is sliced.Subsequently, cuts are made in curved thermoplastic resin portions onthe right and left in the portion E. Finally, cuts are made from thesupporting fabric 4 side while leaving the unstretchable members 3flawless. In this instance, cuts are made so that the thermoplasticresin 2 of about several millimeters (for example, 1 to 2 mm) is left onthe periphery of the long slender unstretchable members 3. Theconfiguration is the same in this regard as in the case described withreference to FIGS. 2A through 2C.

Subsequently, as is shown in FIG. 5, a section 1B between the portions Eand F of the resin long body 1 is placed in the induction heating coilserving as the induction heating portion 6, so that the unstretchablemembers 3 in the section 1B are inductively heated.

The basic change in state caused by this induction heating is the sameas in the case described with reference to FIG. 3. However, in contrastto the case of FIGS. 4A and 4B where a part of the resin long body 1 isseparated completely, as are shown in FIGS. 6A and 6B, the thermoplasticresin portion in the section 1B is left intact and instead theunstretchable members 3 are peeled off from the thermoplastic resin 2 inthis case.

In this case, too, in order to maintain the temperature of theunstretchable members 3, which are the subjects to be heated, at aconstant temperature (for example, about 200° C. to 250° C. in the caseof urethane) or in a predetermined pattern during the induction heating,a dummy load 8 made of the same material as the unstretchable members 3is placed in the induction heating coil serving as the induction heatingportion 6. A temperature rise of the dummy load 8 during the inductionheating is monitored by the thermo couple 7 and fed back to the controlsystem of the induction heating portion 6.

In addition, the induction heating portion 6 may be controlled not onlyto maintain the temperature of the unstretchable members 3 but also tomaintain the hardness of the thermoplastic resin 2 that is softened dueto influences of the unstretchable members 3 heated by the inductionheating portion 6 at a predetermined value.

In a state as are shown in FIGS. 6A and 6B where the unstretchablemembers 3 are peeled off from the resin long body 1, the surface(thermoplastic resin) of the resin long body 1 in a portion where theunstretchable members 3 have been peeled off is roughened. It istherefore preferable to apply a process to smoothen this surface.

The procedure to interlink the end portions of the resin long body 1processed as above will now be described.

FIGS. 7A and 7B show a state where the both ends of the resin long body1 are opposed to each other after the unstretchable members 3 exposedfrom the respective end portions are cut diagonally to arrange the shapein order to link the resin long body 1 whose end portions have beenprocessed as has been described with reference to FIG. 3 through FIG.6B.

Initially, as are shown in FIGS. 8A and 8B, from the state in FIGS. 7Aand 7B, exposed portions of the unstretchable members 3 being exposedare coated, for example, with a sheet of supplementary thermoplasticresin 9 in order to fix the unstretchable members 3 being exposed whilethe end portions of the resin long body 1 are held in a state where theunstretchable members 3 being exposed in the one end portion and in theother end portion are butt-connected to each other. Subsequently, theunstretchable members 3 are fixed by heating these portions using aheating block 10.

Then, as are shown in FIGS. 9A and 9B, a connection fabric 12, such as acanvas, is laminated to a portion where there is a cut in the supportingfabric 4 using an adhesive or the like from the under side of the resinlong body 1. The connected portion in this state is set in a die 13shown in FIGS. 10A and 10B. For example, a sheet of thermoplastic resin11 for design surface is applied to a portion where the end portions ofthe resin long portion 1 are butt-connected to each other. Then, afterthe die 13 is closed, the die 13 is heated by passing a current toheaters 17 in the die 13.

Accordingly, the portions where the end portions of the resin long body1 are butt-connected are melted and joined to each other. Thereafter,the current flowing into the heaters 17 is stopped and the resin longbody 1 connected in the form of a loop is taken out after the die 13 iscooled. Referring to FIGS. 10A and 10B, numeral 14 denotes an upper die,numeral 15 denotes a lower die, and numeral 16 denotes a center core.

As has been described, according to the first embodiment, in theconnection method of a resin long body for interconnecting the endportions of the resin long body 1 in which the conductive unstretchablemembers 3 are embedded within thermoplastic resin 2 along thelongitudinal direction, the unstretchable members 3 in each of thespecific sections at the both end portions of the resin long body 1 areheated by the induction heating portion 6, so that the thermoplasticresin 2 coating the unstretchable members 3 is removed by melting forthe unstretchable members 3 to be exposed, after which the both endportions of the resin long body 1 are connected while they are held in astate where the unstretchable members 3 being exposed in one end portionand in the other end portion are butt-connected to each other.Accordingly, in a case where the end portions of the resin long memberto be used for the handrail of a passenger conveyer or the like areinterconnected, the thermoplastic resin 2 and the unstretchable member 3can be separated in a short time and in a reliable manner by applyingthe heating process using induction heating. The work efficiency can betherefore enhanced (the induction heating is characterized by its highefficiency and fast temperature rising because a subject to be heateddirectly generates heat).

Also, by applying induction heating in such a manner that thetemperature of the unstretchable members 3, which are the subjects to beheated, is maintained at a predetermined value or in a predeterminedpattern during the induction heating, it is possible to process the endportions without impairing the quality and the function as the resinlong body 1, such as the moving handrail of a passenger conveyer.

Further, by controlling the induction heating portion in such a mannerso as to maintain the hardness of the thermoplastic resin 2 that issoftened due to influences of the unstretchable member 3 at apredetermined value during the induction heating, it is possible tosuppress deterioration of the quality and function of the thermoplasticresin 2, such as the hardness.

Second Embodiment

FIGS. 11A and 11B and FIGS. 12A and 12B are views used to describe amanner in which the unstretchable members 3 at the both end portions arephysically connected to each other when interconnecting the end portionsof the resin long body on the basis the connection method of the resinlong body of the first embodiment above.

In the first embodiment above, as are shown in FIGS. 7A and 7B, theunstretchable members 3 in the both end portions are cut diagonallyfirst and thence butt-connected to each other. A purpose of thisconfiguration is to ensure the strength in a connected portion where theend portions of the resin long body 1 are interconnected in a case wherethe resin long body 1 is used as the moving handrail of a passengerconveyor or an escalator. In other words, in a case where thebutt-connected portions of the unstretchable members 3 are concentratedwhen the cross section of the moving handrail is viewed at right angleswith respect to the traveling axis, because the mechanical strengthtotally depends on the thermoplastic resin alone, the strength islowered.

In the second embodiment, in order to further enhance the strength inthe connected portion where the end portions of the resin long body 1are interconnected, as a method for physically connecting the respectiveunstretchable members 3, as is shown in FIGS. 11A and 11B, theunstretchable members 3 being exposed are cut at right angles withrespect to the longitudinal direction to arrange the shape and the bothends of the resin long body 1 are opposed to each other. In this state,the cut portions of the unstretchable members 3 are placed on aconnection supporting plate 19 when the both ends of the resin long body1 are butt-connected to each other as are shown in FIGS. 12A and 12B.The portion is then heated by means of induction heating or the likeusing a heating coil 18 to raise the temperature of this portion. Aphysical connection (for example, brazing, soldering, welding, bonding,and so forth) is thus applied.

Consequently, it becomes possible to increase the mechanical strength inthe portion where the end portions of the resin long body 1 areinterconnected. In addition, because all of the unstretchable members 3can be cut in the same length and butt-connected, it becomes possible toshorten the portions in the end portions of the resin long body 1 towhich the process is applied. The workability can be therefore enhancedand it is possible to achieve an effect that leads to a reduction of theprocessing time.

FIGS. 13A and 13B show an example where the respective unstretchablemembers 3 are connected. Herein, the respective unstretchable members 3are connected with connection materials 21, such as brazing, usingconnection caps 20, such as steel rings, as connection supportingmembers for connecting the respective unstretchable members 3. In a casewhere the connection caps 20 are used, when the unstretchable members 3are butt-connected to each other, the connected portion can be coveredentirely with a metal material. It is therefore possible to achieve aneffect that the mechanical strength can be further increased.

FIG. 14 is a view showing a case where the connection caps 20 are fixedby caulking as another example where the respective unstretchablemembers 3 are connected. In this case, there is no need to heat theconnected portion. Hence, in addition to the effect described above, theworkability can be enhanced further and it is possible to achieve aneffect that leads to a reduction of the processing time.

The connection supporting members, such as the connection caps 20, maybe used in the form of separate individual elements or a set of morethan one connection cap 20 linked together.

Various modifications and alterations of this invention will be apparentto those skilled in the art without departing from the scope and spiritof this invention, and it should be understood that this is not limitedto the illustrative embodiments set forth herein.

1. A connection method of a thermoplastic resin long body forinterconnecting end portions of a long body made of thermoplastic resinin which conductive substantially unstretchable members are embeddedwithin the thermoplastic resin along a longitudinal direction, themethod comprising: heating the unstretchable members in each of specificsections in both end portions of the thermoplastic resin long body usingan induction heating portion; exposing the unstretchable member byremoving the thermoplastic resin coating the unstretchable membersinterconnecting, the both end portions while the both end portions areheld in a state where the unstretchable members have been exposed in oneend portion and in the other end portion and are butt-connected to eachother.
 2. The connection method of a thermoplastic resin long bodyaccording to claim 1, further comprising: controlling a temperature ofthe unstretchable members heated by the induction heating portion so asto be maintained at a constant temperature or in a predeterminedtemperature pattern.
 3. The connection method of a thermoplastic resinlong body according to claim 1, further comprising: controlling ahardness of the thermoplastic resin that is softened due to an influenceof the unstretchable members heated by the induction heating portion isat a predetermined value.
 4. The connection method of a thermoplasticresin long body according to claim 1, further comprising: physicallyconnecting the unstretchable members that are exposed in the one endportion and in the other end portion to each other.
 5. The connectionmethod of a thermoplastic resin long body according to claim 4, furthercomprising: heating the unstretchable members being exposed in the oneend portion and in the other end portion by induction heating while theend portions are physically connected to each other.
 6. The connectionmethod of a thermoplastic resin long body according to claim 4, furthercomprising: connecting the unstretchable members being exposed in theone end portion and in the other end portion to each other using aconnection supporting member.
 7. The connection method of athermoplastic resin long body according to claim 1, wherein: theunstretchable members are a plurality of long slender copper cables. 8.The connection method of a thermoplastic resin long body according toclaim 1, wherein: the thermoplastic resin long body is a moving handrailof one of a passenger conveyer and an escalator.